This invention relates to rotary regenerative heat exchangers of the type comprising two main parts relatively rotatable with respect to each other about a common central axis, a first of said main parts constituting a regenerator body comprising an inner cylindrical post shell and an outer cylindrical shell interconnected with said inner shell by a plurality of radial partition walls forming a plurality of open-ended sectorial compartments containing a regenerative heat transferring mass providing passages for flow of fluid media therethrough from and to the ends of the regenerative body, and the second of said main parts constituting a duct part providing ducts having inlets and outlets for flow of heat emitting and heat absorbing fluid media to and from the opposite ends of said regenerator body, at least one of the ends of said outer shell being provided with a sealing ring positioned in the clearance between said main parts.
In rotary regenerative heat exchange apparatus of a common type referred to, a cylindrical rotor carrying the compartments of heat absorbent material is first exposed to a flow of heating fluid such as hot exhaust gas that is directed through a limited portion of the rotor. Upon rotating the rotor about its axis, the heated heat absorbent material is positioned in the path of a relatively cool fluid to be heated such as air, whereby the heat of the gas may be transferred thereto. The rotor is surrounded by a housing including a stationary duct part that simultaneously directs the heat emitting and heat absorbing fluids through spaced compartments of the rotor.
The rotor is subjected to a substantial temperature gradient whereby the structural components thereof warp and distort to the extent that effective sealing between the rotor and enclosing housing is difficult if not impossible to obtain.
It is therefore a primary object of this invention to provide a rotary regenerative heat exchanger whose sealing surfaces are not subject to the usual excesses of thermal distortion.
Due to a non-uniform temperature distribution, and especially under certain conditions, such as overload, the thermal deformation of the structural components, as the radial partition walls, often results in fracture of weld joints and other damage involving deformation of the sealing surfaces.
Therefore it is also an object of this invention to provide a rotor or regenerator body in which the weld joints are relieved from dangerous stresses.
A known regenerative heat exchanger having a cylindrical rotor carrying heat transfer material and having rigid sealing rings is shown in U.S. Pat. No. 2,981,521, and a similar heat exchanger is shown in British Pat. No. 1,376,122. In both cases the sealing rings are fixedly attached to rigid radial or diametric partition walls or webs the thermal expansion of which in the radial direction gives rise to deformation of the sealing rings.
Another known rotary regenerative heat exchanger is shown in British patent specification 1,046,16 in which the heavy heat transferring mass is supported by rigid radial diaphragms extending radially outward from the post shell to the concentric rotor shell forming a part of the sealing means and subjected to radial deformation forces.